Accessory Ossicles in the Region of the Foot and Ankle: An Epidemiologic Survey in a Jordanian Population.

Background and Objectives: The incidence of accessory bones in the region of foot and ankle is quite variable between studies and are often confused with avulsion fractures in trauma patients with musculoskeletal injuries. The aim of this study was to assess the incidence of accessory ossicles of the foot and ankle according to gender, side and coexistence, and to determine how frequently accessory ossicles were misdiagnosed as avulsion fractures. Materials and Methods: Oblique and/or lateral foot radiographs of 1000 adult patients referred from emergency departments to foot and ankle clinic were retrospectively reviewed for the presence of accessory ossicles. The Kappa statistic was used in order to assess the validity of radiographic interpretation for the presence of these bones. Results: Accessory ossicles were detected in 40.2% of the radiographs. The incidence rates for the accessory ossicles in order of frequency were: Os trigonum (15.4%), accessory navicular (13.7%), os peroneum (11.5%), os vesalianum (1.1%), os supranaviculare (0.7%), os subfibulare (0.6%), os talotibiale (0.4%), os calcaneus secundarius (0.3%), os supratalare (0.3%), os infranaviculare (0.3%), os intermetatarseum (0.2%), and os subtibiale (0.1%). Coexistence of two or three ossicles in the same foot was observed in 4.4% of the cases, mostly coexistence with os peroneum (2.9%), followed by accessory navicular (1.6%). 2.7% of accessory ossicles were initially misdiagnosed as avulsion fractures at emergency departments. Interrater agreement over identification of different accessory ossicles was found to be reasonably reliable, with a Kappa greater than 0.80 for all assessed bones. Conclusions: In clinical practice, a thorough knowledge of normal anatomical variants is essential to facilitate appropriate diagnosis and treatment and can help to prevent diagnostic errors.

Incidence of symptomatic os trigonum among nonathletic patients with ankle sprain.

PURPOSE: Os trigonum syndrome is a rare condition, often affecting athletes. A paucity of data exists on the incidence of os trigonum syndrome in nonathletic population. The study aimed to determine the incidence and clinical characteristics of os trigonum syndrome in nonathletic patients with sprained ankles. METHODS: The sample consisted of 798 adolescent and adult patients that attended the emergency department or Foot and Ankle Clinic with acute ankle sprain. Lateral and/or oblique lateral radiographs of the feet were screened for the presence of os trigonum in relation to age and gender. A cohort of 163 patients with os trigonum was followed up prospectively over a 48-month period to correlate the presence of the os trigonum with patient symptomatology. RESULTS: Os trigonum was found in 20.4% (163/798) of sprained ankles. Patients aged 18-35 exhibited most os trigonum [42.3% (69/163)], with higher incidence in females. 5.5% (9/163) of the os trigonum patients developed an os trigonum syndrome after a standard treatment of an ankle sprain [3.8% (3/78) of males and 7.1% (6/85) of females]. Females aged between 18 and 35 years had higher incidence of os trigonum syndrome compared to males of a similar age. CONCLUSION: Os trigonum syndrome should be suspected in nonathletic patients with an ankle sprain unresponsive to standard treatment. About 1.1% of acute ankle sprain patients develop an os trigonum syndrome. This finding can help identify the source of a patient's symptoms, leading to an accurate diagnosis, appropriate treatment and reducing the potential chronic symptoms.

Incidence and anatomical variations of accessory navicular bone in patients with foot pain: A retrospective radiographic analysis.

The accessory navicular (AN) is an accessory ossicle anatomically located on the medial side of the foot, proximal to the navicular and continuous with the tibialis posterior tendon. It is occasionally a source of pain and local tenderness. Knowledge of the AN and its morphological variations can help identify the source of a patient's symptoms and prevent misinterpreting them as fractures. Foot radiographs from 1,240 patients who presented in two centers with chronic foot pain, or persistent pain developed after trauma, were retrospectively reviewed to determine the incidence and variations of the AN in relation to gender. The AN was found in 20.9% (259/1240). Among 259 feet with AN, Type 1 was identified in 25.4% (66/259), Type 2 in 42.4% (110/259) (20.0% (52/259) Type 2 A and 22.4% (58/259) Type 2B), and Type 3 in 32.0% (83/259). After 13 patients with incomplete medical records had been excluded, the remaining records showed that foot pain was associated with an AN in 10.6% of patients (26/246). In 1.2% of cases, two additional ossicles were found proximal to the navicular, possibly the result of multiple ossification centers that did not unite at the time of development. Patient symptomatology was related to the presence of an AN in 2% of patients with chronic foot pain. The AN could vary morphologically. Our data can enhance our diagnostic skills in detecting these ossicles. Clin. Anat. 30:436-444, 2017. © 2017 Wiley Periodicals, Inc.